Capacity value of photovoltaic systems and their impacts on power system reliability

This paper investigates the various aspects of the capacity value of photovoltaic systems (PV-systems) and the effect of their penetration levels on power system reliability. Unlike wind power, the available output power of PV-systems can be classified into two specific time periods: certainly unavailable during the night and uncertainly available during the day. In other words, during the night, the output power is zero while during the day the output power experience uncertainties due to, among others, clouds and humidity. Therefore, this mixed behavior cannot be modeled as a stochastic variable during all time periods. The output power of PV-systems is clustered into bands and convolved with the output power of the conventional generators to determine the reliability indices and the capacity value. The IEEE RTS is used to demonstrate the effects of different strategies in calculating the capacity values of PV-systems. The results not only show that the capacity value is different for the two case scenarios but also the it decreases in a semi-linear manner as the size of the PV-system increases. Sequential Monte Carlo simulation is utilized to validate the results.